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| United States Patent |
5,642,698
|
|
Diehl
, et al.
|
July 1, 1997
|
Induction system for internal combustion engine
Abstract
An induction system for a multicylinder internal combustion engine includes
a log for receiving air drawn into the engine and individual runners
extending from the log to intake ports of the engine. An antireversion air
manifold supplied with air by the log has flow control valves and branches
extending between a main passage of the antireversion air manifold and the
individual intake manifold runners, with the branches connecting with the
runners at positions situated between individual throttle plates and
intake valves.
| Inventors:
|
Diehl; Roy Edward (Northville, MI);
Vance; Matt Adrian (Dearborn, MI)
|
| Assignee:
|
Ford Motor Company (Dearborn, MI)
|
| Appl. No.:
|
697100 |
| Filed:
|
August 19, 1996 |
| Current U.S. Class: |
123/184.42; 123/184.54 |
| Intern'l Class: |
F02M 035/10 |
| Field of Search: |
123/184.42,184.47,184.54,339
|
References Cited
U.S. Patent Documents
| 3606871 | Sep., 1971 | Gropp et al. | 123/409.
|
| 3814069 | Jun., 1974 | Croft et al. | 123/184.
|
| 4089349 | May., 1978 | Schenk | 137/859.
|
| 4231329 | Nov., 1980 | Ishida | 123/184.
|
| 4492249 | Jan., 1985 | Arino et al. | 137/515.
|
| 4651766 | Mar., 1987 | Ransom | 137/116.
|
| 4760833 | Aug., 1988 | Tatyrek | 123/574.
|
| 4771740 | Sep., 1988 | Koike | 123/184.
|
| 4901680 | Feb., 1990 | Matsumoto | 123/184.
|
| 4953447 | Sep., 1990 | Bender | 60/397.
|
| 5014654 | May., 1991 | Ishibashi | 123/568.
|
| 5117738 | Jun., 1992 | Horner, Jr. | 137/854.
|
| Foreign Patent Documents |
| 0167836 | Jan., 1986 | EP | 123/184.
|
| 1-224421 | Sep., 1989 | JP | 123/184.
|
Primary Examiner: Okonsky; David A.
Attorney, Agent or Firm: Drouillard; Jerome R.
Claims
We claim:
1. An induction system for a multicylinder internal combustion engine,
comprising:
a log for receiving air drawn into the engine;
a plurality of runners extending from the log to a plurality of intake
ports associated with the cylinders of the engine;
a plurality of throttle plates situated within said runners, with at least
one throttle plate in each runner;
an antireversion air manifold system supplied with air by said log and
having a main passage and a plurality of branches, with at least one
branch extending from the main passage to each of said runners at a
location between the throttle plate and the intake port; and
a plurality of flow control valves, with one flow control valve being
positioned in each of said branches such that airflow is allowed within
said branches in the direction from said main passage into said ports, but
reversion flow is prevented from said ports into said main passage.
2. An induction system according to claim 1, further comprising an engine
speed control valve positioned in an air bypass passage extending from the
log to the main passage of the antireversion air manifold system.
3. An induction system according to claim 1, further comprising a pressure
sensor positioned in the main passage of the antireversion air manifold
system.
4. An induction system according to claim 1, further comprising a vacuum
chamber operatively connected with said log and with the main passage of
the antireversion air manifold system.
5. An induction system according to claim 4, further comprising a crankcase
ventilation system operatively connected with said vacuum chamber.
6. An induction system according to claim 4, further comprising an exhaust
gas recirculation system operatively connected with said vacuum chamber.
7. An induction system according to claim 4, further comprising an air
cleaner for supplying air to the log.
8. An induction system according to claim 1, wherein each of said flow
control valves comprises a check valve.
9. An induction system for a multicylinder internal combustion engine,
comprising:
a log, attached to an air cleaner, for receiving air drawn into the engine;
a plurality of runners extending from the log to a plurality of intake
ports associated with the cylinders of the engine;
a plurality of throttle plates situated within said runners, with one
throttle plate in each runner;
an antireversion air manifold system operatively connected with and
supplied with air by said log and having a main passage and a plurality of
branches extending from the main passage to the intake ports, with the
flow of air from the log to the main passage being controlled by an engine
speed control valve positioned in an air bypass passage extending from the
log to the main passage; and
a plurality of flow control check valves, with one flow control check valve
being positioned in each of said branches such that airflow is allowed
within said branches in the direction from said main passage and into said
ports, but reversion flow is prevented from said ports and into said main
passage.
10. An induction system according to claim 9, further comprising a pressure
sensor positioned in the main passage of the antireversion air manifold
system.
11. An induction system according to claim 9, further comprising a vacuum
chamber operatively connected between said log and the main passage of the
antireversion air manifold system.
12. An induction system according to claim 9, further comprising a
crankcase ventilation system operatively connected with said vacuum
chamber.
13. An induction system for a multicylinder internal combustion engine,
comprising:
a log, operatively associated with an air cleaner, for receiving air drawn
into the engine;
a plurality of runners extending from the log to a plurality of intake
ports associated with the cylinders of the engine, with a single runner, a
single associated intake port, and a single intake valve serving each
cylinder of the engine;
a plurality of throttle plates situated within said runners, with one
throttle plate in each runner;
an antireversion air manifold system operatively connected with and
supplied with air by said log and having a main passage and a plurality of
branches extending from the main passage to the intake ports, with a
single branch extending from the main passage to each of the intake ports,
and with the flow of air from the log to the main passage being controlled
by a control valve positioned in an air bypass passage extending from the
log to the main passage of the antireversion air manifold system; and
a plurality of flow control check valves, with one flow control check valve
being positioned in each of said branches such that airflow is allowed
within said branches in the direction from said main passage and into said
ports, but reversion flow is prevented from said ports and into said main
passage, with the result that during idle and part throttle operation of
an engine equipped with the present induction system the air pressure
within the volume of each runner extending between the mating intake port
and the mating throttle valve will increase.
14. An induction system according to claim 13, further comprising a
pressure sensor positioned in the main passage of the antireversion air
manifold system, so as to measure the pressure within the cylinders at the
time the intake valve of each cylinder closes.
15. An induction system according to claim 13, further comprising a vacuum
chamber operatively connected with said log and the main passage of the
antireversion air manifold system.
16. An induction system according to claim 15, further comprising an
exhaust gas recirculation system operatively connected with said vacuum
chamber.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an induction system for a multicylinder
internal combustion engine in which a plurality of port-throttled intake
runners is supplied with air by a single unthrottled air log.
2. Disclosure Information
Internal combustion engines typically include one or more throttle plates
positioned either as a single throttle plate in an air log upstream of
individual cylinder runners or within the individual cylinder runners
themselves. If a single air throttle plate is used far upstream of the
intake valves positioned at the various cylinders, the pressure of the
entire manifold must change if the quantity of air flowing through the
manifold is to change in response to an altered throttle angle, as
prompted by the operator, whether it be a human operator or, for that
matter, an automotive speed control. Of course, any change of the air
pressure within an entire intake manifold will be accompanied by a time
lag in the response of the engine.
Automotive designers seeking to avoid throttle response problems have
produced intake manifolds or induction systems using individual throttle
plates mounted at the bottom of the intake runners close to the intake
valves. Such a configuration allows good throttle response by limiting the
volume of the manifold which is subjected to subatmospheric, i.e., vacuum,
pressure. However, if a source of engine vacuum is needed either to draw
gases from the engine crankcase as in a positive crankcase ventilation
system, or to recirculate exhaust gas, or to operate various vacuum
powered devices such as a power brake booster or motors associated with a
climate control system of the vehicle, it is necessary to place vacuum
taps into the intake runners between the individual throttle plates in the
intake valves. One automotive engine marketed by Bayerische Motoren Werke
(BMW) utilizes such a scheme, in which an air manifold is connected with
individual pipes running to the inlet runners between the individual
throttle plates and intake valves. Unfortunately, the BMW system has no
control valves located in the individual pipes or branches extending
between intake runners and the air manifold. As a result, the pressure
within each of the manifold runners is lowered to a vacuum or
subatmospheric level because the individual cylinders are interconnected
by the air manifold. Because the cylinders are lowered to subatmospheric
pressure, the BMW system will operate with a pumping loss that is avoided
by a system according to the present invention.
SUMMARY OF THE INVENTION
An induction system for a multicylinder internal combustion engine includes
a log for receiving air drawn into the engine, and a plurality of runners
extending from the log to a plurality of intake ports associated with the
cylinders of the engine. A plurality of throttle plates is situated within
the runners with at least one throttle plate in each runner. An
antireversion air manifold system is supplied with air by the log and has
a main passage and a plurality of branches, with at least one branch
extending from the main passage of antireversion air manifold to each of
the runners at a location between the throttle plate and the intake port
being serviced by any particular runner. A plurality of flow control
valves is used according to the present invention, with one flow control
valve being positioned in each of the branches, such that airflow is
allowed within the branches in the direction from the main passage of the
antireversion manifold into the ports, but reversion flow is prevented
from the ports into the main passage of the antireversion air manifold.
According to another aspect of the present invention, an idle speed control
valve is positioned in the an air supply passage extending from the log to
the main passage of the antireversion air manifold. An air pressure sensor
may be advantageously positioned in the main passage of the antireversion
air manifold. A vacuum chamber operatively connected with the log and with
the main passage of the antireversion air manifold may be advantageously
used as a vacuum reservoir and mixing tank for introduction crankcase
ventilation gases and/or recirculated exhaust gas, as well as a vacuum
source for a brake booster or other vacuum operated devices.
It is an advantage of the present invention that an engine equipped with
the present induction system will have superior idle and part throttle
fuel consumption characteristics, because the air pressure within the
portion and inlet runner extending between the intake valve and the
individual throttle plate of each cylinder will be allowed to come up to
atmospheric level when the intake valve for the particular cylinder is
closed; because this pressure clearly exceeds any vacuum pressure, the
pumping work required to move air into the engine cylinders during the
intake stroke of each particular cylinder will be reduced. In fact, in
actual engine testing the inventors of the present invention have observed
a fuel economy benefit of up to 8%, as compared with conventional
multicylinder induction systems having a single throttle plate.
Other advantages as well as objects and features of the present invention
will become apparent to the reader of this specification.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates an induction system according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
As shown in the FIGURE, an induction system for a multicylinder internal
combustion engine includes log 10 which is fed air which first passes
through air cleaner 12. Notice that no throttle is supplied to the air
entering log 10. Air passing through log 10 then passes through intake
runners 14, and after passing over individual throttle plates 18 and past
intake valves 22, which are located in intake port 16, the intake air
enters the engine cylinders (not shown).
During idle operation of an engine equipped with the present induction
system, the air required to supply the engine enters the engine cylinders
via bypass passage 30 which extends between log 10 and engine speed
control valve 32. After passing through engine speed control valve 32, the
air enters a final section of bypass passage 30 and then enters vacuum
chamber 34.
Vacuum chamber 34, as its name implies, operates at subatmospheric pressure
at all times. When any particular cylinder, (in this case there are six in
the illustrated embodiment), is operating in its intake stroke during
either idle or part throttle operation, air will pass from vacuum chamber
34 and through main passage 24 of the antireversion air manifold system.
After entering and passing through main passage 24, the air will pass into
one of branches 26 in response to the vacuum originating at the particular
cylinder which is on its induction or intake stroke. After entering branch
26, the air will be pulled through one of flow control valves 28, which is
illustrated as being a check valve, but which could comprise another type
of control valve drawn from the class of those such valves known to those
skilled in the art and suggested by this disclosure. After passing through
control valve 28, the air enters one of runners 14 at a position between
throttle plate 18 and port 16.
Because each of the cylinders of the engine subjects main passage 24 to
vacuum during the induction stroke of each particular cylinder, main
passage 24 and vacuum chamber 34 will be held at a vacuum. Because chamber
34 is at a vacuum, chamber 34 is useful for introducing crankcase gases
through PCV entry tube 38 and recirculated exhaust gas (EGR) through EGR
supply tube 42. Upon entering vacuum chamber 34, the PCV and EGR gases
will be mixed and distributed through main passage 24 to the various
cylinders. Similarly, vacuum chamber 34 may be used as a source of vacuum
for brake booster vacuum supply tube 40 and, for that matter, for any
other vacuum driven devices employed in a vehicle having an engine with an
induction system according to the present invention.
An engine having an antireversion manifold system according to the present
invention is well suited to the use of a manifold pressure sensor, 36,
which provides information needed to operate the engine with a
speed-density type of electronic fuel injection system.
Attention is now drawn to the particular function of flow control valves
28. Notice that flow control valves 28 permit flow in the direction from
main passage 24 and into runners 14, but prevent reversion flow from
runners 14 into main passage 24. Thus, when any one particular cylinder is
on its intake stroke, each of the individual flow control valves 28, with
the sole exception of the control valve associated with the cylinder
operating in its intake stroke, will be closed. As a result, the pressure
of the intake runners 14 of the cylinders which are not on their intake
strokes will be unaffected, and the remaining cylinders, i.e., those
cylinders not on their intake strokes, will remain at atmospheric
pressure. Thus, the engine will not needlessly evacuate the intake runners
to a pressure below atmospheric pressure. This is important because the
thermodynamic efficiency of an engine equipped with an induction system
according to the present invention will be superior to an engine which
lacks the flow control valves 28 found with the present system.
A system according to the present invention provides a further advantage
inasmuch as the present system may be more easily produced than
conventional ported throttle systems because air leakage past the various
throttle plates will not result in a flow of air to the other cylinders of
the engine; for all practical purposes, idle air flow is controlled only by
engine speed control valve 32, because airflow through valve 32 would
overwhelm leakage past any one particular throttle plate 18.
While the invention has been shown and described in its preferred
embodiments, it will be clear to those skilled in the arts to which it
pertains that many changes and modifications may be made thereto without
departing from the scope of the invention.
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